Radio Controlled Helicopters

An rc helicopter is just like the real thing only smaller and flies in the same way. You have different elements that control different aspects of maneuverability - main rotor, pitch of the blades, tail rotor etc., and each channel on your handset will control one elements’ function. The more channels you are able to control, the greater the range of maneuverability of your model.

Learning to control your first rc helicopter is tricky and you should start with just 2 channels controlling up/down and left/right movement.

Master hovering first, then get to grips with left and right. Additional channels allow you backward and forward flight and things become more complex as the number of channels increases. By the time you are up to 6 channels you should be able to perform aerial acrobatics with your rc helicopter!
References :
http:/www.radio-controlledhelicopters.net
http://www.radio-controlledhelicopters.net/article_info.php?articles_id=2

If you want to control the RC HELICOPTERS flying, you need a radio transmitter(where you can move the stick to control the rc movement). The channel is related with how many part that you will control, such as if you only want to move the 2 part(such as throttle and turn) so you need only 2 channel. In RC HELICOPTERS model, there are more channel needed, and the common used is 6 channel(6chs).Hope it help
If you want to know more about rc helisopters, please check it ot
References :
http://aerofunmen.blogspot.com